Extensible ladder



(fie Model.)

T. R. PARK.

EXTENSIBLE LADDER. No. 322,632. Patented July 21, 1885.

WITNESSES: v I I IN'VENTOB:

' 4M5 BY ATTORNEYS.

UNITED STATES PATENT OFFICE;

THOMAS R, PARK, OF PARKERSBURG, VEST VIRGINIA.

EXTENSIBLE LADDER.

SPECIFICATIQN forming part of Letters Patent No. 322,632, dated July 21, 1885.

Application filed March 10, 1885. (No model.)

To all whom, it may concern:

Be it known that I, THOMAS E. PARK, of Parkersburg, in the county of lVood and State of lVest Virginia, have invented a new and Improved Extensible Ladder, of which the following is a full, clear, and exact description.

My invention relates to extensible ladders, and has for its objectto facilitate the extension and contraction of the ladder and provide for automatic and secure locking of the laddersections in line when extended, and also to promote safety in the use of the ladder as a lire-escape, for which service it is especially designed.

The invention consists in various peculiarities of construction of parts of the ladder and in various combinations of said parts, all as hereinafter fully described and claimed.

Reference is to be had to the accompanying drawings, forming part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure lis a side view of my extension-ladder made in three sections, and shown contracted,as when out of use, and partly broken away. Fig. 2 is a sectional side elevation of the ladder as extended for use, and partly broken away and in section, Fig; 3 is a front elevation of one of the side bars of the extension-ladder, showing the joints or couplings between the three ladder-sections. Fig. 4 is a cross-section through one of the couplings, taken on the line a: m, Fig. 2; and Fig. 5'is an inside perspective view of the lower end of one of the ladder-bars.

The extension-ladder may be made in any desired number of sections, according to the desired length of reach. I show it made in three sections-a central section, A, an upper section, B, and a lower or ground section, 0.

The section B preferably has hooks b fixed to the upper ends of its side bars, and may have light retaining-springs b to hold the hooks into engagement with a bar across a window or the top bar or rail of a balcony when the extension-ladder is used as a fire-escape,and said section Bis not providedwith the guide-plates D on'its side bars, as are the sections A O, and the ladder-section O has no hand-rails or guides E 011 its side bars, as are provided on the sections A B, and the lower ends, 0, of the side bars of section 0 are rounded off, or may be pointed to rest 011 the ground; otherwise the ladder-sections A B G are alike; and as the section A embodies all the distinctive features of my ladder, a detailed description of said section,with its end couplings and connections to the sections B G,will suffice for a clear understanding of the invention.

The upper ends of the side bars of laddersection A are beveled downward at their back edges, as at a, so as to lie fairly over the beveled edges Z) of the side bars of section B when the ladder is extended, and the lower ends of the side bars of section A are beveled downward and backward from the front, as at a, to be overlapped by the beveled edges 0 of the side bars of section 0. v

At the joints of the lower ends ofthe side bars of the ladder-section A with the upper ends of the side bars of ladder-section O the ends of section A are provided with metal plates F, which are bent preferably into E form in cross-section, so as to lieat one of their faces closely to the side bars, where they are firmly secured; but their upper parts or plates, f, stand away from the beveled faces a of the bars for about the thickness ofthe parts 9 of the angular or j-shaped plates G, which plates lie by one face against the outer sides or faces of the upper ends of the side bars of ladder-section O, the parts 9 of plates G standing away from the beveled faces 0 of section 0 for a distance about equal to the thickness of the parts f of plates F. The plates F G thus constitute a coupling, the parts f g of which form interlocking tongues, having shoulders f g, respectively, at their ends; and I prefer to form the projecting lips f g on the ends of tongues f 9, so that when the end shoulders, f g, abut the angles or end bends of the plates G F, respectively, when the ladder-sections are extended, the said lips f E will pass through the apertures g f at the end bends of plates G F, respectively, thereby making additional interlocking connections of the ladder-bar couplings to prevent lateral play of the extended laddersections on each other, the laps or bends of 1 the tongues f g from opposite sides of the ladder-bars being, however, mainly depended on e saaesa to prevent lateral disengagement of the couplings.

The coupling between the ends of the side bars of ladder-sections A B is formed of plates F G, substantially like those last above described.

When the ladder-sections are extended, spring-catches H, fixed on the side bars of one section, look into notches h on the ends of the other section to hold the sections firmly in line with each other.

. I show catches H fixed to the lower sect-ions to look into notches it formed in the upper sections; but the catches may be on the upper sections, and the notches in the lower sections, if desired.

To each side bar of ladderscction A a bar or rail, E, is fixed, the upper end of the bar being bent downward, as at e, and secured to the ladder-bar, and at the back or lower end each bar E is inclined, as ate, parallel with the adjacent beveled end of the ladder-section, and is bent at the end, as at e, and made fast to the ladder-bar, so that pins I, which are fixed to the bars of the next lower laddersection to project laterally therefrom just beneath the bars E when the ladder-sections are contracted, will, while the ladder-sections are being extended, run along beneath bars E until they strike the inclined portions 6 of the bars, which will guide the upper ladder-section down to and in line with the next lower section, so that the coupling-plates G F engage each other.

About at the places where the bends or inclines e of bars E com menee,I support the bars by braces E, which are fixed to the ladder side bars and are shaped properly to let the pins I pass by them.

The pins I of lower section, 0, engage the bars E of section A, and the pins I of section A engage the bars E of the upper section, B. It is evident that the guide-bars E at each side of the ladder serve also as ahand-rail for persons going up or down the ladder- To more certainly secure the interlocking of the plates F G, I make their lips f sufficiently long to project somewhat beyond the plane of the adjacent edges of the ladder-bars, and to provide for the sections lying fiat upon each other when the ladder is contracted and without damaging thelips f 2 g; and also to give room for the lips while the ladder-sections are being contracted or extended, I form grooves J K along the opposite edges, respectively, of the ladder-section A, and a' groove, L, in the lower edge of section 0, and a groove, M, in the upper edge of section B.

The guides D consist of metallic plates fastened by screws or otherwise to the opposite side bars of the ladder-sections A O, and these plates D have int-urned flanges d at their lower edges which enter grooves O in the outer faces of the side bars of the sections A B when the ladder is contracted, as in Fig. 1, and the flanges pass through notches in the side edges of the coupling-tongues f of plates F,

. V V m l l j the fiangesd escaping from the grooves O 0 just as the pins I strike the inclines e of bars E as theladder is being extended.

The rounds R of the ladder-sections may be placed at any desired distance apart.

It'is evident thatthe ladder may very quickly be extended foruse as a fire-escape in emergencies, and that it will be useful for any ordinary service required of a ladder, and the ladder will stand stiffly and firmly, so as to carry quite as heavy weight as a ladder having sidebars made in one piece.

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. An extensible ladder made in sections, having side bars beveled at their joining ends, as at a b, and said beveled ends being provided with plates F G, bent, respectively, at oppo site sides of the ladder-bars at the joints, and provided with interlocking tongues f g, substantially as herein set forth.

2. An extensibleladder made in sections,having side bars beveled at their joining ends, as at a b, and said beveled ends being provided with metal plates formed with interlocking tongues fg, and said tongues having lips f adapted to enter holes f, respectively, formed at the bases of the tongues, substantially as herein set forth.

3. An extensible ladder made in sections, having side bars beveled at the adjoining ends, as at a b, and said beveled ends being provided with plates F G, bent, respectively, at opposite sides of the ladder-bars at their joints, and provided with interlocking tongues f q, and said tongues having lips f 9 adapted to pass into holes f, respectively, at the bases of the tongues, substantially as herein set forth.

4. An extensible ladder made in sections, having side bars beveled at their joining ends, as at a b, and said beveled ends being provided with metal plates formed with interlocking tongues fg, respectively, in combination with spring-catches H on one ladder-section locking into notches hon the adjacent section, substantially as herein set forth.

5. An extensible ladder made in sections, having side bars beveled at their adjoining ends, and said beveled ends being provided with metal plates formed with interlocking tongues f g, respectively, and said tongues having lips f adapted to enter holes 9 f at the bases of the tongues, and the tongues being prolonged beyond the plane of the ladder-bars, which bars have grooves, as at J K L M, to accommodate the lips f g, substantially as herein set forth. V

6. An extensible ladder made in sections, having side bars beveled at their joining ends, as at a b, and said beveled ends being provided with metal plates formed with interlocking tongues f g, respectively, in combination with guide-plates D,fixed to one ladder-section,and provided with bent flangesd,entering slots 0, formed in the adjacent ladder-section, substantially as herein set forth.

7. An extensible ladder made in sections,

having side bars beveled at their joining ends, as at a b, and saidbeveled ends beingprovided with metal plates formed with interlocking tongues f g, respectively, and the upper end of one ladder-section being provided withlaterally-projecting pins I, in combination with bars E on the next upperladde1--section,which bars have inclined port-ions e,compelling the coupling of the joint-tongues f g, substantially as herein set forth.

8. As an improved article of manufacture, a coupling for extensible ladders, consisting of plates F G, having an angular cross-sectional form and converging to a bend at one end, so as to provide interlocking tongues f y herein set forth.

THOMAS R. PARK. Witnesses:

W. H. HUNTER, (bus. '1. CALDWELL. 

